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Biomedical subjects

M Hamada

Publications and source records attributed to M Hamada.

At least 667 records · Page 37Linked to original sources
PubMed1975

A glyoxalase I inhibitor of a new structural type produced by Streptomyces.

Many streptomyces strains produced an inhibitor of crude glyoxalase prepared from rat liver which did not inhibit glyoxalase I prepared from yeast. Another inhibitor, C11H14O6, which inhibited glyoxalases prepared from both rat liver and yeast was obtained from a cultured broth of Streptomyces griseosproeus and crystallized. Preincubation of this inhibitor with reuduced glutathione increased its inhibitory activity, which suggested its reaction with reduced glutathione. It showed a strong inhibition of growth of HeLa cells and inhibition of Ehrlich ascites carcinoma by daily injection. It also showed weak inhibition of the solid type of Ehrlich carcinoma and prolonged the survival period of mice inoculated with L-1210 cells.

Animals↗
PubMed1975

Purification properties and subunit composition of pig heart lipoate acetyltransferase.

Lipoate acetyltransferase [acetyl-CoA: dihydrolipoate S-acetyl-transferase, EC 2.3.1.12], the core enzyme of the pyruvate dehydrogenase complex, has been highly purified by gel chromatography on Sepharose 6B and sucrose density gradient centrifugation in the presence of potassium iodide. The native enzyme has a sedimentation coefficient (S020,W) of 26.7S and a diffusion coefficient (D020,W) of 1.25 x 10(-7) cm2.-sec-1. The weight-average molecular weight was estimated to be 1.8 million from the sedimentation equilibrium data. The content of right-handed alpha helix in the enzyme molecule was estimated to be about 25% by optical rotatory dispersion and about 22% from the circular dichroism spectra. The enzyme was found to contain about 23 moles of protein-bound lipoic acid per mole of enzyme; some other properties are also reported. Lipoate acetyltransferase dissociated to yield a single subunit with a molecular weight of 74,000 as estimated by polyacrylamide gel electrophoresis in sodium dodecyl sulfate and by gel filtration on Bio-Gel in 6 M guanidine-HCl. The molecular weight was also estimated to be 74,000 from sedimentation equilibrium data in 6 M guanidine-HCl] containing 0.1 M 2-mercaptoethanol. Evidence is presented that 1 molecule of lipoate acetyltransferase apparently consists of 24 very similar subunits, each of which contains NH2-terminal alanine. Each subunit contains 1 molecule of covalently bound lipoic acid.

Acetyltransferases↗